Electrically-driven drill.



W. P. TROTTER.

ELEGTRIOALLY DRIVEN DRILL.

APPLICATION FILED DBO. 31, 1907, 1 086 797; Patented Feb. 10, 1914.

2' SHEETS-SHEET 1.

Wit" eases \3 j Am) Cumin;

P. TRO-TTER. ELEGTRIGALLY DRIVEN DRILL.

APPLICATION FILED DEC. 31, 1907.

Patented Feb. 10, 1914.

2 SHEETS-BEBE?! 2.

UNITED STATES PATENT OFFICE.

WALTER F. TROTTER, 0F CHARLESTON, WEST: VIBGINIA,,AS SIGNOB TO THEJEFFREY MANUFACTURING COMPANY, A CORPORATION OF OHIO.

ELECTRIOALLY-DBIVEN DRILL.

Specification of Letters Patent.

Patented Feb. 10, 1914.

Application filed December 31, 1907. Serial No. 408,756.

tain new and useful Improvements in Electrically Dr.iven. Drills,of'which. the follow ing is a specification, reference being had thereinto. the accompanying drawing.

This invention relates to electrically driven mining. machines and-more.especiallyto drills such as are used in .coal mines. for boring holestoreceive explosive charges and for other-purposes.

.The ob eet of this invention-sis to. provide; a drillof the-classspecifiedhaving improved means ;of power transmission, improved means.of feeding and. such:;other improvements as-are evident from thefollowing specification.

-In some mines explosive gases. are met with and serious explosionsvresult if there be any exposed flame orisparks in the regionwhere Such.gases-collect. Asis. well known, the direct current motors commonlyused. in driving drills ,frequentlycause sparks and flames of suchnature that:ex.-- 'plosive gases of the kind found in these mines willbe.fired. .I, therefore, preferto inclose all of the electrical parts ofmy drill in such a way that any. sparks which may form cannot becommunicated to the external atmosphere.

In the accompanying drawingsin which is illustrated a practicalembodiment of my improvements, Figure 1; is a perspective view of thedrill and. its support. Fig. 2 is a vertical I longitudinal sectionthrough the drill, with the feed screw omitted. Fig. 3 is a rear endelevation of the drilL. Figs-4 and 5 are side and end elevations ofthefeed nut detached and shown onan enlarged scale.

I have shown my improved drill supported upon an adjustable frame Aadapted to engage the floor and roof of the mine and rovide a firmsupport. The -motor B has its field frame 1, provided on either sidewith trunnions 2 whiclnare pivotally. supported in the sliding blocks or..clamps A, which engage the channel side .bars. A of ;the.supportingframe. with thlsieone stru'ction the motor may swing. about; a.horizontal axis, may be raised or lowered and the. firame as a whole is,capable of swing ng bodily upon a vertical axis, thus providing auniversally adjustable support for; the drill.

The field frame, 1 .carriesdhe oles 3-4, with the usual windings .at 3The armature 5 mounted upon-a hollow shaft 6 which has supportingbearings at 7-8,

mounted=in endplates=9 and .10, of the mo, tor frame. Theseendplates-areboltedto the sides oredges-of'the field framein a manner totightly inclose the field and armature. The plate 10 is formed withanextension oro -set 1.0. toreceive the'commutator- 21 and brushes 22which are mounted upon insulating-blocks23 on the inner wall of theextension 140. .Into thefront end of theshaftis is threaded the pinion11. This piniommeshes with .upperja-nd lowerxspur gears, 12 whicharefastonshafts 13. These shafts, 13.- -have bearing supports at .13 intheend, plate .9, -and\at 13F. unthe plate 14 which ,forms one side .ofa. earcasing 14, this gear casing being, .pre erably cast in one withthe plate 9, as shown. Each of the'shaftsl3 carries a pinion. l5 andthese pinions meslrwith the sg r gear 16 rigidly mountedon the .sleevelThis sleeve has a. :long bearingsupport. in the extension 18 of. the.plateleifi; The drill.,screw 20 .is mounted inthe-hollow shaft 6 andthe sleeve 17 and is adapted to be rotated by the ribs Omsplines, 1750fthesleevel'Z 'which sliding'lgv engage the grooves 20 .of the screw. Atits front. end. the screw carries a drillbit as.2t and at its rear end Iprovide a handle 68. 1

.Thefeeding device is designated as an entirety by. 25. This feedingdevice is of the type shown and described in m pending application forapatent, filed eptem ber 7., 1906, Ser. No. 333,697. As my. presentinvention relates in part to-improvementsin feeding devices of thischaracter, I will, therefore, describe in detail the feeding mechanism.

26 is. a shell bolted upon the shouldered end 18 of the extension 18 andhaving mounted upon its forward reduced end thrust collars 27 and ballcage 28 of the thrust bearing.

29 is-a. casing mounted upon the front of the shell 26 and having acover 30 screwed into its front end. '6 The cover has a l inclosed thatany flame due to sparking or laterally extending boss 3O which is boredout to receive the pin 31.

The feednut proper, 32, comprising the two semi-cylindrical sectionsisarranged in front of the cover 30 and is held rigidly in position by thecasing 33.

This casing is made up ofv an upper part 34 and a lower part 35 whichare formed with hollow bosses 34-35 to receive bosses 32 which projectfrom the respective sections of the nut 32. Screw bolts 36 and 37 arethreaded into the bosses 32 and assist in securing the feed nut andcasing rigidly together. The upper and lower sections 34-35 of thecasing are provided on one side with hinge lugs 34 and 35 which arepivotally mounted on the pin 31 carried by the bearing casing cover 30.On their opposite sides the casing sections 3435 are provided withclamping lugs, those at 34 on the upper section carrying the eye-bolt 38which has its nut 39 in engagement with the lower side of the lugs 35 onthe lower section of the casing. Each of these sections is formed at itsrear end with an out-turned flange, which flanges abut the casing cover30 and which are provided at one side with the fingers or lugs 3435which are designed to embrace the cylindrical boss 30 carried by thecover 30.

It will be seen that with the construction provided, the feed nuttogether with its casing 33 is, so far as rotational movement isconcerned, rigid with the casing 29-30 of the thrust bearing. To preventthe rotation of these parts the casing member 29 is grooved at 29 toreceive a friction band 40, which is provided with clamping lugs 40which carry a clamping bolt 41. On the side opposite the clamping bolt,the friction band is provided with a laterally projecting lug 40designed to engage an abutment 42 which is bolted to the shell 26. It isclear that the clamping action of the band 40 may be varied by adjustingthe tension on the bolt 41, so that the feed nut may be locked rigidlyagainst rotation or may be permitted to have a slow rotationcorresponding to the slippage between the friction band 40 and thecasing 29.

At the commutator end of the armature shaft, I provide a collar 45 whichis provided with internal splines 45* to engage the grooves of the drillscrew and which is centrall supported by the casing shell 46 secure tothe casing part 10*. This collar helps to properly support the drillscrew and to prevent its coming in contact with the rapidly rotatinarmature shaft 6.

I have already pointed out that the end plates 9 and 10 in connectionwith the field rame form a casing which tightly incloses the field,armature, commutator and brushes. In this way these parts are renderedflame proof, that is'to say, they are so thoroughly arcing within thecasing can not pass to the outside of the casing to ignite any explosivegases that might be present in the surrounding atmosphere.

'47 designates as an entirety the combined starting box and connectionbox. That which I prefer and have shown in the drawings is similar tothat shown and described in the pending application of Frank L.Sessions, filed February 18th, 1908, Ser. No. 416,546. This starting andconnection box is entirely inclosed by the flame proof casing 48 and isattached to the motor frame by means of the screws 49.

57 represents the operating lever, by means of which the motor isstarted. As shown in Fig. 3, this operating lever is at the On positionand is held in place by the spring catch 58. When this catch 58 isreleased, the operating lever 57 will move automatically to the Offposition.

47 are plug openings adapted to receive the supply circuit terminals andare so constructed that the terminals may be inserted or removed withoutany sparks being communicated to the external atmosphere.

In the operation of my improved drill, its supporting frame A is firstclamped in a suitable position between the floor and roof of the mineand the motor is adjusted to the desired height. Then by grasping thehandle 68 on the rear end of the drill screw, the latter may be swung tothe desired angle. The terminal sockets of the supply conductors are nowinserted to engage the motor terminals and the starting handle moved tothe On position. The rotation of the armature is transmitted through thereducing gearing consisting of the pinion 11, spur gears 12, pinions 15and spur gear 16 to the sleeve 17, which in turn rotates the feed screw.If now the friction band 40 is tight enough to prevent rotation of thefeed nut, the drill Wlll be fed forward in its rotation at the maximumrate. But if there is slippage between the friction band and the feednut, the rate of feed will be roportionally diminished. Furthermore, ift e drill strikes exceptionally hard material slippage may occur at thefriction band and thus breakage of some of the parts which mightotherwise occur is obviated.

If explosive gases are present in the mine in which the machine is beingused there is little or no danger of exploslons occurring by reason ofthe flame proof construction which has been setforth.

What I claim is:

1. In an electric-coal and rock drill, the combination of the motorhousing, the motor shaft, detachable end walls for the housing, one ofthe said end walls being formed inwardly at its center to provide atubular support for the motor shaft bearing, the

outer edges of the said end wall flanged outwardly in the form of acasing, the cover for the casing separable on lines parallel to a theaxis of the shaft, the tubular extension formed at the center of thesaid cover, the drill shaft journaled in'the said tubular extension, andthe drill feeding devices secured on the outer end of the said tubularextension.

2. In an electric coal and rock drill, the combination of the motorhousing, the motor shaft,detachable end walls for the housing, one ofthe said end walls bein formed inwardly at its center to provi e atubular support for the motor shaft bearings, the outer edges of saidend wall flanged outward to provide a gear casing, the drill shaft andears intermediate the motor shaft and drill s iaft and containedentirely within the said casing.

3. In an electric coal or rock drill, the combination of the motorshaft, the motor housing, the detachable end walls of the said housing,one of the said end walls being formed inwardly at its center to providea motor shaft bearing support, the outer edges of the said end wallflanged outwardly in the form of a casing, the cover for the casingseparable on lines arallel to the axis of the shaft, the drill sha tjournaled in the said casing cover, and the intermediate gearshaft, the,cover for the casing ing contained within the casing, the said gearingtransmitting 1power from the motor shaft to the drill sha v 4. In anelectric coal or rock drill, the combination of the motor shaft, thefield frame, the end walls detachably secured to the field frame andinclosing the motor, one of the said end walls formed inwardly at itscenter to provide a support for the motor shaft bearing, the outer edgesof the said end wall formed outwardly away from the.

the said intermediate gearin shafts.

In testimon whereof I afiix my signature, in presence 0 two witnesses.

WALTER F. TROTTER.

Witnesses:

J N0. 0. Ecxnnr, J. J. SULLIVAN.

